Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=56190
AsyncContext.complete() should close the response. dispatch() should be used if further output to the response is required.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1574923 13f79535-47bb-0310-9956-ffa450edef68
Update changelog

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1574936 13f79535-47bb-0310-9956-ffa450edef68